There have been proposed various forms of walking assistance devices that assist movement of a lower limb of a person who has become unable to walk by himself or herself owing to a diminished muscle power that is typically caused by an injury, disease or aging. Such a device may be used not only for aiding the effort required for the user to walk but also for aiding the rehabilitation of the user who is in the process of regaining the capability to walk.
Such a device typically comprises a C-shaped pelvic frame extending from a lower back of the user to either side of the pelvis, a pair of power actuators attached to corresponding side parts of the pelvic frame and a pair of power transmitting arms each having a first end attached to the output end of the corresponding power actuator and a second end connected to a support member for the thigh or leg of the user. See Japanese patent laid open publication No. 2004-344305 (patent document 1), and Japanese patent laid open publication No. 2006-320350 (patent document 2), for instance.
Patent document 2 discloses a device that incorporates a power actuator and a power transmitting arm as an integrated drive unit in such a manner that the drive unit may be detachably attached to a pelvic frame. In particular, the mounting and dismounting of the drive unit on and from the pelvic frame can be readily accomplished without requiring a tool or the like by using a latch mechanism.
However, according to such a conventional arrangement, the user is required to handle the relatively heavy drive unit when attaching and detaching the drive unit to and from the pelvic frame. Therefore, the user experiences some difficulty in attaching the drive unit to the pelvic frame, after wearing the pelvic frame, by himself or herself, and often requires the help of a caretaker when attaching the drive unit to the pelvic frame.
The user may also be able to attach the drive unit to the pelvic frame before wearing the pelvic frame, but may experience some difficulty in wearing the pelvic frame which is burdened by the weight of the drive unit. Therefore, the user may require a help of a caretaker.